Citrus Industry News

A Lively World Under the Tree

Sarah Strauss

The vast diversity of organisms in soil can have positive impacts on citrus, Sarah Strauss told growers and others at a July seminar in Immokalee.

“Potentially, though we haven’t verified this, (there are) up to a billion organisms in one gram of soil underneath a citrus tree,” the University of Florida/Institute of Food and Agricultural Sciences soil microbiologist says. “A gram is about the size of a quarter.” The microbes Strauss studies are primarily bacteria, archaea and fungi.

“They all impact citrus trees in a variety of ways — everything from nitrogen and carbon cycling to impacting the growth of roots, to altering soil pH, which then in turn impacts plant growth,” Strauss says.

According to Strauss, there are two ways soil microbiology can help citrus. “There is an indirect way that we can manipulate soil microbiology. And that’s through altering the soil environment to try to enhance the growth of certain organisms that are already in the soil. And then there’s the direct method, which is to add specific organisms to the soil and hope that those have a positive impact by themselves and with the organisms that are already present in the soil,” she explains.

Strauss says there are more questions than answers about the way microbes impact citrus.